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From: =?UTF-8?Q?Philippe_Mathieu-Daud=c3=a9?= <philmd@redhat.com>
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Date: Thu, 11 Oct 2018 17:24:01 +0200
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Subject: Re: [Qemu-devel] [PATCH] chardev: Convert IOReadHandler to read an
 unsigned number of bytes
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To: Paolo Bonzini <pbonzini@redhat.com>, Prasad J Pandit <ppandit@redhat.com>
Cc: Peter Maydell <peter.maydell@linaro.org>, Sagar Karandikar <sagark@eecs.berkeley.edu>, "Michael S. Tsirkin" <mst@redhat.com>, Jan Kiszka <jan.kiszka@siemens.com>, Jason Wang <jasowang@redhat.com>, Palmer Dabbelt <palmer@sifive.com>, qemu-devel@nongnu.org, Markus Armbruster <armbru@redhat.com>, Max Filippov <jcmvbkbc@gmail.com>, Michael Clark <mjc@sifive.com>, Gerd Hoffmann <kraxel@redhat.com>, "Edgar E. Iglesias" <edgar.iglesias@gmail.com>, Stefano Stabellini <sstabellini@kernel.org>, Alberto Garcia <berto@igalia.com>, Li Zhijian <lizhijian@cn.fujitsu.com>, Alexander Graf <agraf@suse.de>, Christian Borntraeger <borntraeger@de.ibm.com>, Antony Pavlov <antonynpavlov@gmail.com>, Anthony Perard <anthony.perard@citrix.com>, =?UTF-8?Q?Marc-Andr=c3=a9_Lureau?= <marcandre.lureau@redhat.com>, Laurent Vivier <lvivier@redhat.com>, Corey Minyard <minyard@acm.org>, Amit Shah <amit@kernel.org>, Alistair Francis <alistair@alistair23.me>, "Dr. David Alan Gilbert" <dgilbert@redhat.com>, Fabien Chouteau <chouteau@adacore.com>, Zhang Chen <zhangckid@gmail.com>, "open list:PXA2XX" <qemu-arm@nongnu.org>, Peter Chubb <peter.chubb@nicta.com.au>, Samuel Thibault <samuel.thibault@ens-lyon.org>, "open list:X86" <xen-devel@lists.xenproject.org>, David Gibson <david@gibson.dropbear.id.au>, Igor Mitsyanko <i.mitsyanko@gmail.com>, Cornelia Huck <cohuck@redhat.com>, "open list:S390 Virtio-ccw" <qemu-s390x@nongnu.org>, Thomas Huth <huth@tuxfamily.org>, Michael Walle <michael@walle.cc>, "open list:sPAPR" <qemu-ppc@nongnu.org>, Bastian Koppelmann <kbastian@mail.uni-paderborn.de>

On 11/10/2018 17:14, Paolo Bonzini wrote:
> On 11/10/2018 15:14, Philippe Mathieu-Daudé wrote:
>> The number of bytes can not be negative nor zero.
>>
>> Fixed 2 format string:
>> - hw/char/spapr_vty.c
>> - hw/usb/ccid-card-passthru.c
>>
>> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
>> ---
>> See: https://lists.gnu.org/archive/html/qemu-devel/2018-10/msg02212.html
> 
> Not that easy; you need to adjust qemu_chr_be_can_write,
> qemu_chr_be_write_impl, qemu_chr_be_write (which is where the callbacks
> are invoked).

OK.

> On the other hand, fd_chr_read_poll is not an IOCanReadHandler, and this
> patch therefore probably doesn't compile?

It does compile.

fd_chr_update_read_handler() uses fd_chr_read_poll with io_add_watch_poll():

GSource *io_add_watch_poll(Chardev *chr,
                        QIOChannel *ioc,
                        IOCanReadHandler *fd_can_read,
                        QIOChannelFunc fd_read,
                        gpointer user_data,
                        GMainContext *context);